1. Field of the Invention
This disclosure is related to the field of electrical wiring, and more particularly to systems, methods, and apparatus pertaining to an intelligent multi-way electric switch.
Electrical systems commonly include manual switching systems comprising a switch element combined into a three-way or four-way wiring geometry to provide users with the ability to operate a circuit from multiple locations. For example, it is desirable, and often required by building code, to have a light switch at each entrance to a room. However, if the switches are wired in serial, every switch must be “on” for the light to work. Likewise, if the switches are wired in parallel, every switch must be “off” for the light to turn off. Instead, multi-way wiring geometries are used to cause each switch to operate as a toggle. The circuit has two states—“on” (powered) and “off” (unpowered)—and operating any one of the switches causes the circuit to change to the opposite state—unpowered circuits receive power and turn on, and powered circuits turn off.
In a typical and simple “on/off” switch operating a single circuit, the power supply coming into the building flows to the device which will ultimately receive electrical power. This device may be a light fixture, a wall receptacle, or any other device (or set of devices). The device or devices consuming power are known as the “load.” For electricity to flow, there must be a complete electrical circuit between the electrical power source and the load. This means that the “wire” from the source to the load is actually at least two wires—a powered or “hot” wire that contains electrical current flowing to the load (conventionally known in the art as the “black” wire due to the typical color of the non-conductive sheathing surrounding it), and a “neutral” wire that allows current to flow back to the source (conventionally, the “white” wire), completing the circuit. Thus, a simple on/off switch is essentially a movable section of the circuit that causes the circuit to be complete or broken when a user flips the external switch component. That is, when the switch is in the “on” position, the circuit is complete and the electrical potential causes electrical current to flow to the load, providing it with power (and thus, if the load is a light, causing the light to turn on). When the switch moved to the “off” position, the circuit is broken, electrons stop flowing, and the load receives no substantial current, causing the light to turn off.
A three-way switch operates on the same fundamental principles, except that an additional wire is required so that the function of turning power on/off works, regardless of which of the two switches is operated, and regardless of the state of the other switch. This is essentially done by wiring the two switches together with an additional wire so that any time one of the switches changes state, the circuit also changes state.
This can be seen in prior art FIGS. 1A-1D. In FIG. 1A, the circuit (101) includes a hot wire (103) and a neutral wire (105) connected to the load (107) in circuit. In this case the load (107) is a light (107). The hot wire (103) enters a first three-way switch (109A). A section (111) of the hot wire runs from the first switch (109A) to a second three-way switch (109B), and then continues on to the load (107). Also wired between the switches (109A) and (109B) is a switch line (113), conventionally a “red” line due to the typical color of the sheathing. This switch line (113) is what allows the three-way geometry to work.
In FIG. 1A, the light (107) is off and circuit (101) is broken, because there is no path for electric current to flow to the load (107). The power flows through the first switch (109A) and across the switch line (113) to the second switch (109B), but the second switch (109B) is connected to the hot line (103) section (111), leaving no continuous path to the load (107). If either switch (109A) and (109B) is toggled, however, power will flow. As can be seen in FIG. 1B, if the first switch (109A) is toggled, a complete circuit results, as electrons can flow from the hot line (103) to switch one (109A), across section (111) to switch two (109B), and into the load (107). Alternatively, as shown in FIG. 1C, if the second switch (109B) is toggled, power can flow from hot line (103) to switch one (109A), across the switch wire (113) to switch two (109B), and then into the load (107). Similarly, either circuit (101) can be broken by operating either switch (109A) and (109B), causing the light (107) to turn off.
This system requires specialized hardware. This is because the hot (103) and neutral (105) wires are generally bundled within an outer sheathe when run through the walls of a building, and then the sheathe is cut and the individual wires are separated and individually attached to the switch, typically by wrapping the end of each wire around a different metal post or pole on the switch, and tightening a screw that holds the wire to the post. The posts are in turn connected to the internal switch components. For this to work, the switch must have enough posts, in the proper configuration, to support three-way switching. This also means that, at a minimum, the section of bundled wire running between the two switches must have a hot (black) line, a neutral (white) line, and a switch (red) line.
Similar techniques and hardware have been developed for four-way switching. For example, in the depicted prior art embodiment of FIGS. 2A and 2B, four-way switching is implemented using a pair of three-way switches (109A) and (109B) wired to a four-way switch (115). As with three-way switching, the first three-way switch (109A) is connected to the four-way switch (115) using a section (111A) of the hot wire along with a section (113A) of switch wire. Likewise, the four-way switch (115) is connected to a second three-way switch (109B) using a second section of hot wire (111B) and a second section of switch wire (113B). The four-way switch (115) is a double throw/double pull switch, meaning that when the switch is operated, electrical flow through the switch is reversed between the poles. This essentially means that if an electrical path already exists in the system, operating a four-way switch will break the circuit. If electrical flow does not exist, operating a four-way switch will close the circuit. The three-way switches operate as described with respect to prior art FIGS. 1A-1D.
Various attempts have been made to implement a smart multi-way switch via home automation technologies. For example, the load may be a smart device with a single internal switch that communicates wirelessly with remotely placed switches. Thus, when any switch is operated, the device can detect its own state and toggle on/off as needed. However, these systems do not operate in conjunction with existing wiring and hardware.
For example, home automation systems usually require that fixtures and/or switches be replaced with “smart” devices requiring extensive configuration and set-up. This can add expense, hassle, and waste, as the existing equipment is lost. This can be a problem in buildings with antique or non-standard fixtures, where replacement smart fixtures may not be available. Further, if the conventional wiring is replaced by smart systems, system operation is dependent on continuous communication. If communication is disrupted, the system no longer operates. This makes such systems susceptible to catastrophic failure in the very circumstances where the fixture is likely to be needed. For example, during a storm, a single nearby lightning strike could render the components inoperable. Without a conventional wiring system as a fail-safe, these systems are unsuitable for use in many applications. Thus, users who wish to add automation features to a residence or other building are forced to replace major components of the system and lose the security and/or reliability of conventional switching technologies.